In recent years, the market imposes increasingly high requirements on the performance of loudspeaker modules, and the application of sound absorbing particles is increasingly extensive. In the prior art, when sound absorbing particles are applied within a loudspeaker module, usually a small cavity is designed in the rear vocal cavity within the housing of the loudspeaker. The small cavity is filled with the sound absorbing particles, a net cloth is injection molded at a sound penetration hole of the small cavity by integral molding technique to form a sealing device, the small cavity communicates with the vocal cavity via the net cloth, and the sound absorbing particles perform the sound absorption function.
In such a design, in order to ensure that the net cloth can be firmly injection molded on a small cavity, the wall thickness of the small cavity must be designed to be thick enough, for supporting the net cloth. However, that causes the vocal cavity space to reduce, which degrades the sound quality. Furthermore, by using that approach, the injection molding has low yield, and has a high requirement on the injection molding machine, which increases the production cost.